#include <bits/stdc++.h>
using namespace std;
int query(vector<int> islands);
int findEgg(int N, vector<pair<int,int>> bridges){
vector<vector<int>> adj(N+1);
for(auto [u,v] : bridges){
adj[u].push_back(v);
adj[v].push_back(u);
}
vector<int> tin(N+1), tout(N+1), euler;
euler.reserve(N);
function<void(int,int)> dfs = [&](int u,int p){
tin[u] = euler.size();
euler.push_back(u);
for(int v:adj[u])
if(v!=p)
dfs(v,u);
tout[u] = euler.size()-1;
};
dfs(1,0);
int l = 0, r = N-1;
while(l < r){
int mid = (l+r)/2;
vector<int> ask;
for(int i=l;i<=mid;i++)
ask.push_back(euler[i]);
if(query(ask))
r = mid;
else
l = mid+1;
}
return euler[l];
}
